In switch mode power supplies, the maximum output current is directly dependent upon the maximum output swing of the error amplifier of an operational amplifier. The required maximum output swing of the error amplifier is different from the power supply of the system or from the maximum output swing of the operational amplifier and it is difficult to obtain good precision within the operational amplifier. Several techniques have been used to limit the output swing, e.g., components such as Zener diodes may be placed in the output amplifier to clamp the output signal swing. Regulation of the power supply of the amplifier may be used to guarantee a maximum output voltage. In some cases, these applications dissipate a lot of power. Clamping with Zener diodes in the control loop has also been used to limit the output voltage of an operational amplifier.
However, what is needed is a way to minimize power dissipation (energy consumption) when controlling an output swing of an operational amplifier so as not to exceed a reference value.